Celestial projecting apparatus



Nov; 2, 1954 W. GREEN CELESTIAL PROJECTING APPARATUS Filed June 9, 1951 ,INVEIVTOR.

fl rd m fa Qt- F? 2,693,130 CELESTIA'L PROJECTING APPARATUS William Green, Barrington, R. I.

Application June 9, 1951, Serial No. 230,717

lclaims. (Cl. 88- -24) This invention relates to an apparatus for projecting star and planet images into a curved projection field or screen, thus showing for purposes of study and observation the relative brilliance and positions of heavenly bodies as they appear at any season and from any point of observation on the earth.

Projecting apparatus as heretofore known have generally been unable to show star patterns as they appear from terrestrial points at or near the poles. Further, in various types of proposed projectors, portions of the star images are at some seasonal or latitude settings blotted out by structural elements of the projectors structure.

The principal object of the present invention is to provide a projector which permits the showing of the stars as they appear from any point on the earths surface. A further object is to provide a structure whose elements blot out no portion of the star pattern regardless of the position taken by the projector.

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings in which:

Fig. 1 is a view in perspective with parts shown as broken away, and

Fig. 2 is a plan view of the driving mechanism.

The apparatus illustrated comprises a supporting frame which may take the form of a rectangular box 10. In practice this is set up in a level position and the horizontal upper edge of its sides will correspond to the horizon line. To opposite sides of the box are attached bearings 8 and 9 for a cradle in the shape of a yoke 11 pivotally supported at the ends of its arms to rock about a horizontal axis. A fiat plate 12 is attached to the center of the yoke and from this rises a rotatable capstan 13 having a large gear-14 attached to its lower end. A tube 15 is set in the yoke 11 and projects upwardly through the capstan. It is shouldered and enlarged at its lower end to provide a journal for the capstan and to its upper edge is attached a holder for an electric light bulb 16. This bulb is located midway between the arms of the yoke 11 and in its axis of movement.

Surrounding the source of light and supported by the capstan is a hollow shell comprising a cylindrical portion 17, an upper conical frustrum 18 and a lower conical frustrum 19. The cylinder and frustrums form an envelope about and are tangent to a hypothetical sphere whose diameter may be selected as desired but in the present instance may be 16" to The shell is perforated by a plurality of orifices varying in size to conform to the respective brilliance of the stars. The orifices are located at the trigonometrically determined projections of the apparent places of the stars as they would be chartered on the hypothetical sphere. A circle 22 midway between the ends of the cylinder 17 indicates the equator.

The upper frustrum 18 is provided with a sleeve 20 set in its apex and projecting inwardly at right angles to the axis of the yoke and in the major axis of the shell. A corresponding sleeve 21 is set in the apex of the lower fulcrum 19. The sleeves 20 and 21 are of such diameter as to slip over the capstan 13 and to turn thereon with limited frictional engagement. As herein shown the shell is supported by the lower sleeve 21. The shell may be turned by hand upon the capstan or it may be turned mechanically by rotation of the capstan as will be presently described. The shell with the sleeve 21 may be A 2,693,130 Pa en NY-..2..19.54

. 2 lifted o'fi"tl1e.'capstan,jreversed end for end and supported by the 'sle'ev'e zll at the option'of the user.

The 'sleev'e'20 is herein shown "as provided with a cupshaped tubular plug 24 having a flat top perforated to represent those sta'r'swhose apparent places are north of declination plus 87?. The plug 24 is telescopically rec'ei'ved within. the-sleeve 20 and may be removed and similarly inserted in the sleeve 21 when the shell is reversed. It is provided with a segmental cover 25 movable to mask the perforations when the shell is reversed so th'atthe southernjpole is uppermost.

Stars whose "apparentqplaces are in. the zone bounded by parallels of "declination plus 87 and plus 26 /2 are represented by orifices 23 in the frustrum 18. Stars whose apparent places are in the zone bounded by plus 26 /2" and minus 26 /2 are represented by orifices in the cylindrical portion 17 of the shell. Stars in the zone minus 26 /z to minus 87 are represented by orifices in frustrum 19. Perforations in the plug 24 provide for the projected image of stars whose apparent places are within 3 of the pole.

The angular position of the yoke and the shell mounted therein is controlled by an arcuate rack 26 located on one of the side walls of the box 11 concentrically with respect to the horizontal axis of the yoke. The segmental scale 27 indicates the angular setting of the shell, and a locking rod 28 mounted on the adjacent arm of the yoke is arranged to engage the rack 26 at any selected point.

The gear 14 of the capstan is arranged to be rotated through a gear train 29, 30, 31 carried by the plate 12 to the underside of which is attached a small motor 32 having the driving pinion 31. The idler gear 29 may be shifted to the dot-and-dash line position shown in Fig. 2 when it is desired to drive the shell through a reversing gear 33. The motor is provided with flexible leads and with its gear train is bodily moved when the yoke is rocked.

In operation the box 10 is placed on a level support with its top edges in the plane of the horizon. To show the stars as they appear at any given latitude in the northern hemisphere of the earth, the sleeve 21 is placed upon the capstan 13 and the box 10 so oriented that the bulb 16 points toward the north. The yoke is then rocked to a position corresponding to the latitude of the observer and locked in position. The bulb 16 is lighted and the reversing gear of the motor driven train is set so that the gear 14 is driven in the proper position to make the stars appear to rise from the eastern horizon line.

When it is desired to show the star pattern from any point in the southern hemisphere of the earth, the position of the shell is reversed and the tube 20 fitted over the capstan 13. The plug 24 is placed in the sleeve 21 and the yoke set at the angle corresponding to any desired southern latitude. Finally the gear train is adjusted to make the stars appear to rise from the horizon line opposite to that represented in the northern hemisphere. If desired sidereal hours may be represented by vertical lines on the cylindrical portion 17 of the shell. Provision may also be made for indicating the position of the moon in its proper phase, and even the sun appropriately dimmed so that the stars around it may be seen. Due to the well defined horizon and accurately controlled driving mechanism, the changes in time of the rising and setting of the heavenly bodies may be demonstrated as these vary with changing seasons and at different latitudes.

Having thus disclosed my invention and described in detail an illustrative embodiment thereof, I claim as new and desire to secure by Letters Patent:

1. An apparatus for projecting onto a curved projection field images of the sun, moon, planets, and stars comprising: a cradle having a pair of spaced bearings forming a horizontal axis of rotation for said cradle, a frame for supporting said cradle and bearings, a capstan carried by said cradle midway between said bearings and mounted to rotate about an axis intersecting the axis of said cradle at right angles, a source of light located at the intersection point of said axes, means on said frame to fix the angular position of said cradle on said horizontal axis, means to rotate said capstan in either direction, a shell of sheet material having a plurality of imageforming apertures therein, diametrically located sleeves set respectively in the top and bottom of the shell in axial alignment and being of such diameter as to telescope with the capstan whereby each of the sleeves in turn may be fricltionally engaged therewith for rotating the apertured she l.

2. A celestial projecting apparatus comprising a frame, a cradle mounted therein to rock about a horizontal axis, a hollow perforated shell having upper and lower conical end portions and a cylindrical connecting portion, axially aligned sleeves extending inwardly toward each other in said end portions, and a motor driven capstan mounted in the cradle and shaped to engage frictionally with each of said sleeves in turn, whereby the shell may be reversibly connected to the capstan and rotated thereby.

References Cited in the file of this patent Number Number UNITED STATES PATENTS 

